O.K., I do know a little, the Z is obviously a TPI LB9 car and the RS is a TBI L03. But what is different about the internals of those motors, both 305's (compression, cam, etc.?). For 92' there is a 60 horsepower difference on paper beteeen a Z & RS T-5, where is it coming from, can't just be the different injection system and exhaust setup, right???

Thanks in advance for shedding some light...Alex

 

Yes it can, in combination with cam and compression.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

I haved worked on about everything else on a car, but have no experience with engine internals. I am definetly no engine guru and am still learning about the basics, so need some help here please!!! Seems I have seen a lot of guys on this board swap cams in their L03, does that change compression? What does? Does anyone think its worth changing the heads/cam on a low mileage great condition L03 or are they generally just swapping for a 350? I am looking to beef up my L03 to about 250 hp without pulling the motor? I don't need more hp. than that because I doubt the T-5 can handle more and want to keep that as well. What mods would make the most sense?

Alex

 

Static compression is the ratio of the volume of the cylinder with the piston at the bottom divided by the volume of the cylinder with the piston at the top. This is typically changed by the type of piston (dished, which increases the latter volume, or flat-top, which decreases it), or the volume of the chamber in the head - increasing the chamber volume lowers compression. All factory 305 heads have 58cc chambers, so that's not the difference between the engines you ask about. Generally speaking, the higher the static compression ratio, the higher the cylinder pressure obtained during combustion, so more power is produced.

The camshaft controls the opening and closing of the intake and exhaust valves. More power can be gained by opening the valves farther, and by opening them earlier and closing them later with each cycle. There are a lot of factors involved there, people have spent their entire lives trying to improve camshafts, and you really need to define what you want from the car before trying to upgrade the cam (nothing is free - more power can come at the expense of driveability or economy). LO3's did have pretty lame cams, all things considered. BTW, the cam can affect cylinder pressure, but not static compression ratio.

The LO3 heads did not have a very good port design, intended more for economy than power. The World Products 305 heads should make a world of difference. Combine them with cam and exhaust upgrades, talk to the guys on the TBI board about your goals, and you should get to the 250 hp without too much trouble or expense.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

the heads are different, the exaust is different. TPI is perfect for 305. TBI needs a better air cleaner. Stock one sucks(in a bad way )I've only changed that, put on a different muffler(w/tailpipes), and I have 190HP. Full exaust and some minor stuff should have 230HP without getting into the engine at all.

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

I'm not a expert, but from what I have learned the standard LB9 has different heads and exhaust manafolds and maybe a different cam compared to the L03 and it produced 205hp. If the car had the G92 option package, the cam was replaced with the same cam that was in the 350 and was given dual Cats. This configuration is what produced 230hp.



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Bill Rockhold
92 Camaro RS, 305 TBI M5 F41
SCCA Solo2